sourdough quick breads

I found a recipe here for sourdough banana bread[1], which uses a cup of sourdough starter in the batter. I've also made sourdough pancakes. The pancakes had the distinctive sourdough taste (a half cup of the starter fermented all night with the water and flour from the recipe). The banana bread did not. I've made it twice, and both times it just tasted like regular banana bread. Is it that my starter isn't sour enough, or just that the starter is stired in when the bread is mixed, right before going into the oven, and doesn't have time to ferment further? Is it supposed to be that way?